This seems to be a deionization filter that will remove (+) and (-) charged ions in the water as well as a layer of carbon for chlorine and taste. Basically removing all contaminants by the charge on the contaminant ion.

You will also notice that the higher the incoming TDS, the greater the life expectancy will drop. You can also get standard deionization cartridges attached to a separate faucet on your sink. They will work in any standard filter housing.